632 M. L. FULLER APPALACJHIAN OIL FIELD 



in the Trenton and Chazy in New York, while some of the highest natural 

 pressures ever reporte'd, ahout* 1,500 pounds to the square inch/^ were 

 afforded by gas from the lowest beds of the Potsdam, next to the granite, 

 in New York. In the Carboniferous, oil has been found up to horizons 

 300 feet or more above the Pittsburgh coal lying at the base of the Monon- 

 gahela group of the Pennsylvanian series. 



The upper Devonian formations yield the largest proportion of the 

 petroleum afforded by the Appalachian field. There seems to have been 

 abundant material in the shape of vascular plants with resistant tissues, 

 spores, seed envelopes, etcetera, as well as fucoids, algae, and micro- and 

 macro-animal organisms of both marine and fresh-water forms. The 

 abundance of material, in connection with the presence of salt water and 

 the occurrence of good reservoirs and thick shale cap-rocks, made the con- 

 ditions especially favorable to the formation and storage of petroleum. 

 The depth of the strata from the surface has also been a contributing 

 factor of importance in the retention of the oil in a large part of the oil 

 field because of the barrier imposed to upward escape or the entrance of 

 fresh water from above. 



In the Carljoniferous series there are more frequent limestones, and the 

 sandstones are thicker, tending to permit dissemination of the oil. The 

 cap-rocks are thinner, and the nearness of the formations to the surface 

 lessens the resistance to escape and sometimes permits the entrance of 

 fresh waters. Nevertheless, there are several good oil sands in the Car- 

 boniferous in the northern part of the Appalachian field. 



The Trenton lifestone, because of its great depth, is unavailable to 

 wells except where it rises on the flanks of the Cincinnati anticline in 

 central Kentucky, Tennessee, and northern Alabama, west of the main 

 oil belt lying along the west flank of the Appalachians. 



New York. — The greater part of the oil of the State comes from the 

 Bradford and other sands not far above or below it in the Chemung, but 

 traces of oil or gas are found in most of the limestones and sandstones 

 and in several of the shales down to the Potsdam, especially in the 

 Niagara and Trenton limestones, the Oriskany, Medina, and Potsdam 

 sandstones, the Utica shale, etcetera. The formations below the- Chemung, 

 however, lie mostly outside the limits of the Appalachian field proper. 



Pennsylvania and northern West Virginia. — The producing horizons 

 in Pennsylvania and northern West Virginia range from the Carrol sand 

 of the Monongahela formation, 300 feet above the Pittsburgh coal, to the 

 Kane sand of the Chemung, 3,770 feet below the same datum. The Clin- 



ic F. H. Oliphant : "Catalogue of Metric Metal Works for 1909," p. 88. 



